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With slight changes, this can be made tail-recursive, which means the recursion can be elimited completely.

Tail-recursive variant:

sub cleverGuess { my( $lower, $higher ) = @_; my $guess = int(($lower + $higher)/2); print "Guessing: $guess\n"; if ($guess == $ans) { print "The guess was correct!"; return; } elsif ($ans < $guess) { print "Lower..."; $higher = $guess-1; } else { print "Higher..."; $lower = $guess + 1; } cleverGuess($lower, $higher); }

Tail-recursion replaced with a loop:

sub cleverGuess { my( $lower, $higher ) = @_; for (;;) { my $guess = int(($lower + $higher)/2); print "Guessing: $guess\n"; if ($guess == $ans) { print "The guess was correct!"; return; } elsif ($ans < $guess) { print "Lower..."; $higher = $guess-1; } else { print "Higher..."; $lower = $guess + 1; } } }

I don't mean to diminish your effort. I just wish to illustrate that power of recursion is sometimes an illusion. Performance should increase by removing recursion where it's not needed, and now you know how!


In reply to Removeing Unecessary Recursion by ikegami
in thread Behold! The power of recursion. by DigitalKitty

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